The Multi Store Model: Details
Sensory store: has two sub-stores, the Iconic store (vision) and the Echoic store (sound). The type of coding in this store is sensory coding and the duration of this store is limited, 0.5 to 1.5 seconds.
Short Term Memory: This store codes information acoustically. The capacity of STM is 7+/- 2 items and information can be held here for a duration of 15-30 seconds.
Long Term Memory: This store codes information in a semantica or meaningful way. The capacity and duration can last for up to a life time.
The Multi Store Model: Explanation
It is a cognitive theory that suggests when information is coded we attend to it in a specific way. Intially information is taken into sensory memory and if we pay attention to it then the information will pass onto short term memory. If we ignore information then it will decay. For information to pass into long term memory it needs to be rehearsed. If information has been successfully attended to then it will be coded semantically in long term memory, if information is ignored in short term memory then it will decay.
The Multi Store Model: Supporting Research
PETERSON & PETERSON 1959 DURATION OF STM
Aim was to investigate the duraiton of short term memory when rehearsal was prevented. Participants were shown consonant trigams and had to count backwards in order to prevent rehearsal. After a 3 second interval, 80% of trigrams were correctly recalled. After an 18 second interval on 10% could be correctly recalled. The conclusion, short term memory is very short if information cannot be repeated.
BAHRICK ET AL 1975 THE HIGH SCHOOL YEAR BOOK STUDY
This study investigates the duration of very long term memory. 392 ex high school students were palced in one of two conditions: a recall group or recognition group. The recall group had to identify former classmates from photos. The recognition group had to identify former classmates from a list of names and photos. Responses were assessed by comparing their answers with their year books. The recognition group showed a better performance overall.
The Working Memory Model: Explanation
This theory suggests that short term memory includes four component parts. The central executive is what controls the three other components or slave system. The central executive has a limited storage capacity and therefore delegates information processing to the required component, either the visuospatial sketchpad, episodic buffer or phonological loop. The visuospatial sketch pad or inner eye recalls information from the visual part of long term memory. The phonological loop processes auditory information by rehearsing it in the articulatory control system and then storing the acoustically coded items for a short time in the phonological store. The final component of the slave system is the episodic buffer which is required when we need information about evens. The episodic buffer recalls information in the form of episodes from long term memory. The overall suggestion from the theory is that we can carry out multiple tasks in short term memory.
The Working Memory Model: Supporting Research
This study investigated the possiblity of multiple processing tasks within short term memory. 20 chess players were required to remember the positions of 16 chess pieces in ten seconds. In one condition the players had to simultaneously learn letter combinations while the other condition required participants to simultaneously carry out a supression task by saying 'the' in time with a metronome. Participants then had to recreate the chess board.The participants that learned letter combinations performed poorly while those in the other condition performed well. This research concluded that it is possible to carry out multiple tasks within short term memory therefore this research supports the working memory model.
Factors Affecting EWT: Misleading Information
LOFTUS AND PALMER 1974
This study investigates the effect leading questions has on speed estimates. 45 student participants watched 7 videos of a traffic accident. They had to give a general account of what they saw and then aswered some more specific quesitons. The students when answering questions were divided into 5 conditions with 9 participants in each. The separate conditions included one quesiton which had been deliberately manipulated. The original quesiton was ' About how fast were the cars going before they hit each other?' in each condition the verb 'hit' was replaced with either 'smashed', 'collided', 'bumped' or 'contacted'. Participants who had the word smashed in the quesiton estimated the highest speed while participants who had collided in the quesiton estimated the lowest speed. The conclusion to be drawn from these findings is that the wording of a quesiton can alter accurate recall.
Factors Affecting EWT: Anxiety
Loftus wanted to challenge the hypothesis that anxiety enhances recall. In her study she placed conditions into one of two conditions. The first condition involved the participants hearing an intense discussion and then witnessing man exiting a room with a pen and grease on his hands. The second condition involved participants hearing an intense argument and witnessing a man exiting a room with a blood stained knife. Participants in both conditions were then required to identify the person they saw exiting the room from a collection of 50 photos. Those in the first condition had significantly higher accurate recall at 49% compared to the 33% of accurate recall in the second condition. Loftus concluded that anxiety has a negative effect on recall due to the weapon focus phenomenon.
Factors Affecting EWT: Age
FLIN ET AL 1992
This study aimed to investigate the detail and accuracy of recall in adults and children. Flin used three age groups, children aged 5-6, children aged 9-10 and an undergraduate group. All groups were required to watch a presentation on foot hygeine by a nurse. Before the presentation though there was a staged argument between the nurse and her assistants. After the presentation recall from the participants was immediately assessed. Another assessment of recall occurred 5 months later. The immediate recall showed no significant differences between the age groups however the assessment from 5 months later showed that the youngest children remembered significantly less in contrast to the other age groups. The conclusion from this study is that immediate recall of a witnessed event shows know differences in accuracy between adults and children but if there is an interval between an event and recall then children make more errors during recall.
The Cognitive Interview: Improving EWT
The cognitive interview is a specialist form of interview used by police in order to gain the maximum amount of information from witnesses. There are four stages to this interview
- Witnesses are encouraged to recall every detail about the event even if details seem irrelevant or unrelated to the crime
- witnesses should then recreate the context, this could include the weather, how they were feeling or the people around them. The context should act as retrieval cues and prompt memory
- next witnesses should recall the event in a different order i.e. they start with the last thing they remember and then work their way backwards to the beginning of the event. This stimulates the primacy and recency effects
- finally witnesses should imagine the event from another perspective. They should describe the event from another's view point, e.g. the victim or the offender.
The Cognitive Interview: Supporting Research
GIESELMAN ET AL
This study compared the effectiveness of cognitive interviews with standard police interviews. Students were shown videos of violent crimes and then 48 hours later they had to recall the event in either a standard police interview or cognitive interview.
Overall the cognitive interview yielded higher correctly recalled items compared to the standard police interview therefore cognitive interviews are more effective.